My 17mo is just finally easing up on this now that his brother is 2m old. What worked for me was including him in some of baby care. Hand me a diaper. Let's kiss the baby, he's crying and needs love. Good job, you're such a great big brother! Would you like to give baby brother his paci? I'm so proud of you for being such a good helper! Etc. Also, I will NOT engage negative behavior. He wants attention, he doesn't care what kind. If he gets angry and, for example, throws a toy. I tell him one time only that we do not throw our toys. We love, not get angry. Then I ignore until he goes back to being nice. The moment he's nice I engage, give a hug and kiss, and explain that sometimes we have to wait, mama loves you, when you're nice it makes people want to play with you more than if you're mean, etc. And then we clean up his toys if he threw them.

I also set aside one time per day to have special mommy and william time. Usually during DS2 napping, since DS1 only naps once a day now. We do whatever he wants. And just that alone makes the rest of the day SO much better. He just misses having me all to himself.

I keep reinforcing waiting. For example, if he brings me a book while I'm feeding DS2, I tell him he has to wait. Brother needs to eat. Then I make sure to follow through and read him his book after I'm done feeding his brother. I talk to him about it, saying see? I told you we would read, we just had to wait and be patient. Don't worry, mommy didn't forget. He has taken holding on FAR better once I started reiterating that it will happen, just not that second, and then remind him of it as I follow through.

I also remind him when DS2 has to wait. Like when DS1 is in the bath, and DS2 is asleep in my room. If DS2 wakes up, I will tell DS1 that we have to hurry because brother is crying. But then I explain that, see? Brother has to wait sometimes too, just like you do. You both have turns, and that's okay. He doesn't feel as if everything is unfair and just him.

Honestly, it just takes time and adjustment to the new normal. And using every opportunity to show that each child is just as special to mama, and all have their time.

DS1 is VERY routine oriented, so a second child warped his world. But now he realizes that it all still happens in order, just a little earlier or later. And that's okay, because through consistency, he knows it WILL happen.

ETA: We do time out, but only for dangerous things. If he tries to hit the baby, I tell him we don't hit baby brother. He's little and it can hurt him. We love. Let's all hug. Usually that works. But if he's in a hitting mood I warn once that it isn't safe and if he does it again, he will get a time out. If he does it again, I take him to time out in his room and tell him when he's ready to be safe and not hit, he can come out. He's upset for all of 30seconds and then is dancing and happy. So I get him and explain it all again. Then we kiss little brother and I praise him for being loving and not hitting.